The fresh troops come only three days before Friday's opening ceremony and mean that some 18,200 U.K. military personnel are now involved in some capacity in securing the London games — dwarfing the 9,500 British troops now in Afghanistan. The decision followed a Cabinet meeting on venue security.
"On the eve of the largest peacetime event ever staged in this country, ministers are clear that we should leave nothing to chance," Olympics Secretary Jeremy Hunt said in a statement. " The Government continues to have every confidence that we will deliver a safe and secure Games."
The government put the troops on standby a few days ago, but suggested that was merely a prudent contingency measure that was unlikely to be used. Tuesday's announcement is yet another embarrassment for security provider G4S, which has consistently failed to deliver on its Olympic contract.
Thousands of British soldiers have been sent in on short notice to fill the gap in guards. Some of the servicemen have seen their leaves cancelled while others have only recently returned from tours in Afghanistan.
The chief executive of G4S, Nick Buckles, has acknowledged that his company's failure to hire enough Olympic security guards had embarrassed the nation. He made a groveling apology last week when he was questioned by angry British lawmakers at Parliament, who have suggested that "sorry" wasn't enough.
"It was a big disappointment," said Paul Deighton, the chief executive officer of the London organizing committee. "We signed a contract with the biggest security company in the world, whose biggest customer is the U.K. government. They continually assured us that they had both the capability to deliver."
Some lawmakers want G4S, one of the world's largest security providers, to not only pay for all additional costs incurred by the government for bringing in the extra troops but also to face financial penalties for the failing to deliver..
Britain's Prime Minister David Cameron has promised to "go after" G4S if they don't fulfil their contract to make sure the company helps pay for the cost of the additional military personnel. The firm expects to lose between 35 million and 50 million pounds ($54 million-$78 million) on its Olympic contract, equal to about 12 per cent of its annual profit.
Labour lawmaker Margaret Hodge, the chair of the influential Public Accounts Committee and a longtime critic of the G4S contract, says that everything must be done to ensure a safe games but once the Olympics are over, a post mortem is in order.
"They've all got egg on their face," she told The Associated Press on Tuesday.
The security contractor said in a statement it "made very good progress in the last few days" on its commitment to the London organizing committee.
"Significant numbers of candidates are now reaching the final stages of the (security) training and accreditation process each day and we are working hard to ensure that we deliver on the commitments we made," the firm said.
Olympic soccer matches start Wednesday and the games themselves end Aug. 12.
Associated Press Writer Gerald Imray contributed to this story.
Danica Kirka can be reached at http://twitter.com/DanicaKirka